318 (#412) ############################################ CHAPTER XIV THE TESTING OF WOOLS, TOPS AND YARNS, AND EXPERIMENTAL TESTING APPARATUS It is now generally recognized that even the smallest firm should have a small testing laboratory—that all materials should be compared with their standards— and that the productions of any and every firm should go forth accredited under reasonably guaranteed con- ditions. One mistake has often cost a firm many times over the cost of the equipment and maintenance of a suitable laboratory. The following equipment is essential :- 1. Microscope with 2 in., 1 in., and 3 in. objectives, with substage and eyepiece micrometer. 2. Experimental equipment for scouring, carbon- izing, blueing, bleaching, etc. 3. Hand carder (or small experimental set of draw- ing machines followed by knitting machine) for testing colour blends, etc. Lovibond's Tintometer would of course be an admirable addition for a coloured yarn spinner. 4. Conditioning oven. 5. Velvet-covered boards for top drawing. 6. Single thread strength-tester to grasp threads with little or no space in between and up to a short weaving length, say 18 in. 318